The Henry Clay Frick House was the residence of the industrialist and art patron Henry Clay Frick in New York City. The mansion is located between 70th and 71st Street and Fifth Avenue on the Upper East Side of Manhattan. It was constructed in 1912–1914 by Thomas Hastings of Carrère and Hastings. It was transformed into a museum in the mid-1930s and houses the Frick Collection and the Frick Art Reference Library. The house and library were designated a National Historic Landmark in 2008 for their significance in the arts and architecture as a major repository of a Gilded Age art collection. History After Frick's business partnership with Andrew Carnegie started breaking apart, he began spending less time in Pittsburgh, and soon established additional residences in New York and Massachusetts. In 1905, Frick leased the William H. Vanderbilt House at 640 Fifth Avenue. He and his family stayed there for the next nine years. At that time almost every building on Fifth Avenue above 59th Street was a private mansion, with a few private clubs and a hotel. The Andrew Carnegie Mansion was also located on Fifth Avenue at 91st Street. Whether Frick decided to establish himself on the same avenue because of Carnegie is not definitely established. He started looking for a permanent place to set up residence and became interested in the plot on Fifth Avenue between 70th and 71st Street, that was the site of the Lenox Library. The building housed the private collection of philanthropist James Lenox and was designed by the New York architect Richard Morris Hunt in the neo-Greek style. The library was suffering financially, which enabled Frick to acquire the plot in the summer of 1906 for $2.47 million. Four months later, he added an additional parcel of land running some fifty feet east through the block. Due to restrictions placed on the use of the library site, Frick could not take title of the land until 1912, when the Lenox collections were incorporated and moved into the New York Public Library's new Main Branch at Fifth Avenue and 42nd Street. The library building was subsequently torn down that year. Initially Frick sought designs from Daniel Burnham, who was the architect of the Frick Building in downtown Pittsburgh. Burnham submitted a design for an 18th-century Italian palazzo. Ultimately he commissioned architect Thomas Hastings of the firm Carrère and Hastings to design and build